Martin owned a home in Cammeray on the lower north shore of Sydney and wanted to have the area around his new swimming pool paved and landscaped. He contracted with Paul, a local landscaper, for the work to be done on the basis that Martin would supply, at his own expense, all the necessary plants, materials and supplies, and that Paul would supply the labour and any equipment and machinery necessary to do the job. Paul's fee under the contract was $40,000, to be paid upon completion of the job.

A month later, when all the work was done, Paul presented his account for payment to Martin. Martin asked if Paul would accept $25,000 in full settlement of the account, explaining that he had just received a notice from the local council requiring him to upgrade the fence around his swimming pool, in line with new legislation, before it could be certified for use. Martin further explained that, if Paul was prepared to accept this reduction in his contract fee, Martin would be able to get his fencing contractor to complete the work the next day, and thus Martin would be relieved from having to approach his bank for a loan. This would take some time to approve, and would potentially delay the fencing work, and the compliance certificate for the pool, by about a month. Paul, who had earlier greatly appreciated the expensive palm trees that Martin had given him, decided that he would accept the $25,000 in full settlement of the account. Martin immediately paid Paul the $25,000.

Five days later, Paul received an unexpected courier delivery of a case containing half a dozen bottles of expensive Irish whiskey. A note attached to the delivery read: You wouldn't believe it, but two days after the fence was completed and paid for, I won over $500,000 on Lotto! My family and I plan to spend the next few months holidaying in Europe. So, it's live and let live. The booze is a token of my sincere appreciation for the excellent work you did for me on the landscaping. Cheers Martin.

As the situation has changed, Paul now feels that Martin should pay him the full amount of his fee on the landscaping contract.

Using IRAC, advise Paul on his prospects of recovering the $15,000, and in doing so, discuss fully all relevant legal issues that arise in these circumstances. Your answer must be supported with relevant case law authorities.